Michael Westerveld

Effects of smoking and smoking abstinence on cognition in adolescent tobacco smokers.

BACKGROUND In adult animals and humans, nicotine can produce short-term cognitive enhancement and, in some cases, neuroprotection. Recent work in animals, however, suggests that exposure to nicotine during adolescence might be neurotoxic. We tested for evidence of acute and chronic effects of tobacco smoking on cognition in adolescents who smoked tobacco daily and were compared with adolescent nonsmokers. METHODS Verbal working memory, verbal learning and memory, selective, divided, sustained attention, mood, symptoms of nicotine withdrawal, and tobacco craving were examined in 41 adolescent daily smokers and 32 nonsmokers who were similar in age, gender, and education. Analyses were controlled for general intelligence, reading achievement, parental educational attainment, baseline affective symptoms, and lifetime exposure to alcohol and cannabis. RESULTS In adolescent smokers, cessation of tobacco use increased tobacco craving, symptoms of nicotine withdrawal, and depressed mood. Adolescent smokers were found to have impairments in accuracy of working memory performance irrespective of recency of smoking. Performance decrements were more severe with earlier age of onset of smoking. Adolescent smokers experienced further disruption of working memory and verbal memory during smoking cessation. As a group, male smokers initiated smoking at an earlier age than female smokers and were significantly more impaired during tests of selective and divided attention than female smokers and nonsmokers. CONCLUSIONS Adolescent daily tobacco smokers experience acute impairments of verbal memory and working memory after smoking cessation, along with chronic decrements in cognitive performance that are consistent with preclinical evidence that neurotoxic effects of nicotine are more severe when exposure to nicotine occurs at earlier periods in development.

Verbal memory impairment correlates with hippocampal pyramidal cell density

Thirty-five patients with medically refractory epilepsy localized to the temporal lobe (18 left, 17 right) completed the verbal Selective Reminding Test before surgery. Verbal memory impairments existed before surgery regardless of the lateralization of the seizure focus, but patients with left temporal seizure foci were significantly more impaired. After surgical removal of the mesial temporal lobe structures, 2 blinded observers established volumetric cell densities for hippocampal subfields CA1, CA2, CA3, the hilar area, and the granule cell layer of the area dentata. Statistically significant correlations existed between presurgical memory impairment and cell counts (in CA3 and the hilar area, only) for patients with left temporal seizure foci. These findings support the hippocampal model of memory and complement prior research documenting the memory impairments present after surgical removal of the mesial temporal structures.

Global cognitive function in children with epilepsy: A community‐based study

Purpose: To determine the frequency and determinants of subnormal global cognitive function in a representative, community‐based sample of children prospectively identified at the time of initial diagnosis of epilepsy.

Functional MRI of Language Processing: Dependence on Input Modality and Temporal Lobe Epilepsy

Summary:  Purpose: Functional magnetic resonance imaging (MRI) using two language‐comprehension tasks was evaluated to determine its ability to lateralize language processing and identify regions that must be spared in surgery.

Sentence complexity and input modality effects in sentence comprehension: an fMRI study.

Cortical regions engaged by sentence processing were mapped using functional MRI. The influence of input modality (spoken word vs. print input) and parsing difficulty (sentences containing subject-relative vs. object-relative clauses) was assessed. Auditory presentation was associated with pronounced activity at primary auditory cortex and across the superior temporal gyrus bilaterally. Printed sentences by contrast evoked major activity at several posterior sites in the left hemisphere, including the angular gyrus, supramarginal gyrus, and the fusiform gyrus in the occipitotemporal region. In addition, modality-independent regions were isolated, with greatest overlap seen in the inferior frontal gyrus (IFG). With respect to sentence complexity, object-relative sentences evoked heightened responses in comparison to subject-relative sentences at several left hemisphere sites, including IFG, the middle/superior temporal gyrus, and the angular gyrus. These sites showing modulation of activity as a function of sentence type, independent of input mode, arguably form the core of a cortical system essential to sentence parsing.

Specificity in the correlation of verbal memory and hippocampal neuron loss : dissociation of memory language, and verbal intellectual ability

Fifty-nine patients with temporal-lobe epilepsy (28 left, 31 right) completed the Boston Naming Test (BNT), verbal subtests of the Wechsler Adult Intelligence Scale-Revised, and the Logical Memory Subtest of the Wechsler Memory Scale (WMS) before surgery. Performances by patients with left temporal seizure foci were significantly more impaired than those of patients with right seizure foci on the WMS Logical Memory subtest and the BNT. After surgical removal of the mesial temporal lobe structures, two blinded observers established volumetric cell densities for hippocampal subfields CA1, CA2, CA3, the hilar area, and the granule cell layer of area dentata. Statistically significant correlations existed only between percent retention scores and hippocampal neuron loss in CA3 and the hilar area for patients with left temporal seizure foci. None of the other dependent measures was significantly correlated with hippocampal neuron density in any subfield. These results support the hypothesis that certain verbal memory impairments are attributable to hippocampal damage specifically, and not to temporal lobe damage in general.

Multiple subpial transection for intractable partial epilepsy: an international meta-analysis.

Summary:  Purpose: Because the number and variety of patients at any single facility is not sufficient for clinical or statistical analysis, data from six major epilepsy centers that performed multiple subpial transections (MSTs) for medically intractable epilepsy were collected.

Visual confrontation naming following left anterior temporal lobectomy : A comparison of surgical approaches

Change in visual confrontation naming was examined following left (speech dominant) anterior temporal lobectomy (ATL) as a function of surgical technique and patient characteristics. Two hundred seventeen patients with intractable left temporal lobe epilepsy were selected according to standard criteria across 8 centers, and combined into 4 surgical approaches to ATL: (a) tailored resections with intraoperative mapping of eloquent cortex, (b) tailored resections with extraoperative mapping, (c) standard resections with sparing of superior temporal gyrus, and (d) standard resections including excision of superior temporal gyrus. Changes in visual confrontation naming were examined with an index of reliable change derived from an independent sample of 90 nonsurgical patients with complex partial seizures. Results showed significant decline in visual confrontation naming following left ATL, regardless of surgical technique. Across surgical approaches, the risk for decline in visual confrontation naming was associated with a later age of seizure onset and more extensive resection of lateral temporal neocortex.

Impact of Cannabis Use on Brain Function in Adolescents

Abstract: Cannabis is the most common illicit substance used by adolescents. This paper reports results of a pilot study using fMRI and a working memory task to compare brain function of adolescent cannabis users to that of two control groups, one matched for tobacco use and the other for nonsmokers.

Worsening of quality of life after epilepsy surgery Effect of seizures and memory decline

Background: Surgery for intractable temporal lobe epilepsy usually controls seizures and improves health-related quality of life (HRQOL), but some patients experience continued seizures, memory decline, or both. The relative impact of these unfavorable outcomes on HRQOL has not been described. Methods: We studied seizure control, memory change, and HRQOL among 138 patients in the Multicenter Study of Epilepsy Surgery (MSES), an ongoing, prospective study of epilepsy surgery outcomes. Seizure remission at 2 years and 5 years was prospectively determined based upon regularly scheduled follow-up calls to study patients throughout the follow-up period. HRQOL was assessed annually using the Quality of Life in Epilepsy Inventory (QOLIE-89). Memory decline was determined by change in verbal delayed recall from baseline to the 2- or 5-year follow-up. Results: HRQOL improved in patients who were in remission at the 2-year or 5-year follow-up, regardless of memory outcome. Among those not in remission at both 2 and 5 years (25/138, 18%), HRQOL remained stable when memory did not decline (14/138, 10%), but HRQOL declined when memory did decline (11/138, 8%). These 11 patients had baseline characteristics predictive of poor seizure or memory outcome. Declines were most apparent on HRQOL subscales assessing memory, role limitations, and limitations in work, driving, and social activities. Conclusions: After temporal resection, health-related quality of life (HRQOL) improves or remains stable in seizure-free patients despite memory decline, but HRQOL declines when persistent seizures are accompanied by memory decline. These results may be useful in presurgical counseling and identifying patients at risk for poor psychosocial outcome following surgery.